Mikaeus, the Unhallowed, Mindless Automaton, Doubling Season, and Ashnod's Altar

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Mindless Automaton on the battlefield
• Doubling Season on the battlefield
• Ashnod's Altar on the battlefield
• Mindless Automaton has an even number of +1/+1 counters on it

Steps

1. Activate Mindless Automaton's second ability by removing two +1/+1 counters from it, causing you to draw a card
2. Repeat step 1 until Mindless Automaton has zero +1/+1 counters on it
3. Activate Ashnod's Altar by sacrificing Mindless Automaton, adding
4. Mindless Automaton dies, triggering its undying ability, returning it from your graveyard to the battlefield with a total of six +1/+1 counters on it
5. Repeat

Results

• Infinite card draw
• Infinite draw triggers
• Near-infinite colorless mana
• Near-infinite death triggers
• Near-infinite ETB
• Near-infinite LTB
• Near-infinite sacrifice triggers